Advanced petroleum and natural gas production technologies are increasingly used to help meet the demand for energy in both the United States and globally. As conventional resources become scarcer, research and innovation by oil and gas industry has resulted in techniques for tapping unconventional resources, including hydrocarbons trapped in shale formations found in a number of locations throughout the United States. One technology for accessing such resources is hydraulic fracturing, which has transformed natural gas production over the past several years and is also being applied to increase petroleum production. However, new energy supply technologies also bring new environmental management challenges. Among the issues of concern are air pollution emissions from fracturing operations and whether the emissions can potentially impact air quality at wellsites and in surrounding communities. Wellsite emissions may include airborne particulate material released into the airspace surrounding the wellsite during fracturing and other wellsite operations. Wellsite emissions may also include various gasses generated by the wellsite equipment, as well as various gasses released from the Earth's crust into the airspace surrounding the wellsite.
Methods to measure airborne particulate material levels to assess particulate mass flux and dispersion may be implemented during short duration high intensity release of the particulate material during hydraulic fracturing and other wellsite operations. However, the methodologies currently available are intended primarily for large stationary sources.
Pollution emission models to estimate emissions at oil and gas wellsites may be generated based on wellsite activity levels by taking into account emission factors like operating hours, engine ratings, equipment load factors, and other emission factors. The oil and gas industry has been using United States Environmental Protection Agency (EPA) methods to estimate total emissions at oil and gas wellsites. For example, determination of mass of the airborne particulate material may be performed in accordance with the guidance EPA/625/R-96/010a, titled Compendium of Methods for the Determination of Inorganic Compounds in Ambient Air, Compendium Method 10-2.1. The method includes sampling of a large volume of atmosphere, ranging between 57,000 cubic feet (ft3) and 86,000 ft3, with a high-volume blower, typically at a rate ranging between 40 cubic feet per minute (ft3/min) and 60 ft3/min. The high volume sampler may be a compact unit comprising a protective housing, an electric motor driven high-speed, high-volume blower, a filter holder capable of supporting a 203 millimeter (mm) by 254 mm (8 inch by 10 inch) filter, and a flow-controller for controlling the air-flow rate through the sampler.
Another method to obtain representative particulate concentrations during the materials handling operations includes EPA Method 204, titled Criteria and Verification of a Permanent or Temporary Total Enclosure. However, implementing an enclosure over an entire wellsite to capture the particulate material and other emissions generated by the wellsite is impractical and/or impossible.
Tapered element oscillating microbalance (TEOM) samplers may also be utilized by air pollution emissions regulatory agencies and air quality researchers as part of an automated particulate material monitoring system. However, research has shown that TEOM samplers may not report accurate particulate material concentrations due to the operating characteristics of the automated system. TEOM samplers are also too sensitive for operation in the oil and gas environment and, thus, are not a viable alternative for the routine collection of particulate material data at wellsites.